I'm a science journalist and author of "Distant Wanderers: the Search for Planets Beyond the Solar System" who writes about over-the-horizon technology, primarily astronomy and space science. I’m a former Hong Kong bureau chief for Aviation Week & Space Technology magazine and former Paris-based technology correspondent for the Financial Times newspaper who has reported from six continents. A 1998 winner in the Royal Aeronautical Society's Aerospace Journalist of the Year Awards (AJOYA), I’ve interviewed Nobel Prize winners and written about everything from potato blight to dark energy. Previously, I was a film and arts correspondent in New York and Europe, primarily for newspaper outlets like the International Herald Tribune, the Boston Globe and Canada's Globe & Mail. Recently, I've contributed to Scientific American.com, Nature News, Physics World, and Yale Environment 360.com. I'm a current contributor to Astronomy and Sky & Telescope and a correspondent for Renewable Energy World. Twitter @bdorminey

Phobos As First Pit Stop In Manned Mars Exploration

Astronauts may explore the small moons of Mars before a human mission to Mars itself. Credit: Lockheed Martin

Phobos — the enigmatic, oddly-shaped Martian moon — could serve as an eventual pit stop for human missions to the Red Planet.

That’s, of course, contingent on future MarsMars exploration strategies. But even with a diameter of less than 30 kms at its widest, the tiny moon could still offer humans some orbital shielding from galactic cosmic rays (GCRs) and respite from a more costly and potentially risky actual manned Mars surface landing.

Most likely a 4 billion year-old asteroid, captured in an equatorial Mars orbit of less than 6,000 kms, Phobos circles the Martian landscape every 7 hours and 39 minutes. By comparison, Deimos, its longtime lunar companion about half Phobos’ size, has a much longer 30-hour orbit. But because Phobos’ orbit is decaying at a rate of about 2 centimeters per year, it may crash into the Martian surface in as little as 40 million years.

Before it does, Mars researchers would like to sample Phobos’ highly-porous surface.

To that end, as part of NASA Innovative Advanced Concepts (NIAC) program, Stanford University researchers, in collaboration with NASA’s Jet Propulsion Laboratory and M.I.T., have designed a robotic platform prototype for potential use on a Phobos mission.

Four of these one-meter sized, roughly spherical rovers would be deployed from the Phobos Surveyor, a “coffee-table”-sized mother ship that would remain in Phobos orbit. They’re dubbed “Hedgehogs” since they are surrounded by spikes aimed at providing traction in the most difficult microgravity circumstances.

These “Hedgehogs” have been developed with the idea of their potential use in exploring Phobos’ heavily-cratered, dust-covered surface.

In Phobos’ microgravity, the Hedgehogs’ spinning internal wheels would generate torque and cause the rovers to hop, tumble or bound. Marco Pavone, an aerospace engineer at Stanford and the Principal Investigator on the Phobos Surveyor Mission study, says it’s not unlike earth-based tech used in “Clocky” robotic alarm clocks. Such alarms are designed to continually move until their owners actually get out of bed to turn them off.

Pavone says the Hedgehogs’ deployment would be their potential mission’s real challenge.

“You have to make sure that once you deploy these Hedgehog rovers they are captured by Phobos’ gravitational field,” said Pavone. One idea, he says, is to deploy them from just a few kms above the surface so that they have an impact speed of a modest 3-meters per second.

This isn’t the first time that a dedicated mission to Phobos has been seriously discussed or even attempted.

The Soviets tried to do it once in the 1980s, says Pavone. But their first mission to Phobos lost contact just before the spacecraft was to achieve orbit around the Martian moon. Then last year, Russia’s Phobos-Grunt sample return spacecraft crashed into the Pacific before ever leaving earth orbit.

Pavone says his team is trying to develop technology to send to Phobos that will have “higher reliability margins” and “more redundancy” than the Russians’ previous Phobos efforts.

Post Your Comment

Post Your Reply

Forbes writers have the ability to call out member comments they find particularly interesting. Called-out comments are highlighted across the Forbes network. You'll be notified if your comment is called out.